1. Field of the Invention
The present invention generally concerns all racquets such as, commonly, have both (i) strings and (ii) handles.
The present invention particularly concerns (i) the construction of handles, and also shafts if any be present, and (ii) the routing of the strings, of racquets having both strings and handles and/or shafts in order that (i) the length of certain strings may be greatly increased, and, according to this increase, (ii) the dynamics of the racquet response during the striking of balls may be enhanced.
The present invention still further particularly concerns racquets, and particularly racquetball racquets, having long longitudinal strings.
2. Description of the Prior Art
2.1 Previous Racquets of Altered Physical Form and Dynamical Properties
The prior racquet art as taught in the Head patent U.S. Pat. No. 3,999,756; the Durban patent U.S. Pat. No. 4,196,901; the Mortvedt patents U.S. Pat. Nos. 4,531,738 and 4,618,147 (Re. 34,067 and Re. 34,068); and other patents, clearly describe the benefits to playability afforded by maximizing the area, and the attendant main string length, of the striking area of stringed racquets.
An early patent with respect to the altered properties of oversize racquets was U.S. Pat. No. 3,999,756 for a TENNIS RACQUET to Howard Head assigned to Prince Manufacturing, Inc. The well known oversize Prince.RTM. tennis racquet (Prince is a registered trademark of Prince Manufacturing, Inc.) enjoyed excellent market success. As explained in the patent: "t!he racquet has a zone of high coefficient of restitution, much larger than that of conventional racquets, extending in a longitudinal direction from the region of the center of percussion . . . . The zone of high coefficient of percussion is also wider with respect to the corresponding zone on conventional racquets."
Although the analysis in U.S. Pat. No. 3,999,756 is primarily with respect to zones, or areas--the Prince.RTM. tennis being an "oversize" racquet--an analysis of the effect of string length on the force imparted to struck (tennis) balls is particularly contained at FIGS. 13-17 of the patent and in the associated text.
Another patent discussing the effects of both string tension and string length in a racquet is U.S. Pat. No. 4,196,901 to Durban for a TENNIS RACQUET. This patent states at column 2, line 41, et seq. that, "t!o compensate for the absence of transverse bracing in the throat portion of the racquet the longitudinal strings are tensioned somewhat higher than the transverse strings . . . . This tends to spread and stiffen the frame at the throat portion . . . . " It further states at column 2, line 53, et seq., that "w!ith the new, open-throated construction several of the center longitudinal strings will be longer than in a conventional racquet (having a fully elliptical playing head) and the center pair of strings may be as much as 4" longer. This is believed to contribute to the unique "lively action" that players experience using the new racquet."
Several sworn representations were made as to the effect and the utility of longer strings by the same Raymond Mortvedt who is a co-inventor of the present application during of the prosecution of his applications assigned to Ektelon, San Diego (Ektelon.RTM. is a registered trademark of Prince Manufacturing, Inc.), leading to U.S. Pat. Nos. 4,531,738 and 4,618,147. These patents were respectively reissued as U.S. Pat. No. Re. 34,067 for a RACQUETBALL RACQUET WITH INCREASED HITTING AREA IMPROVED RACQUETBALL RACQUET CONSTRUCTION and U.S. Pat. No. Re. 34,068 for a RACQUETBALL RACQUET WITH INCREASED HITTING AREA. It was, for example, stated in AFFIDAVITs of Mr. Mortvedt on Mar. 28, 1990, and Dec. 14, 1994, that "a r!adar gun test, using accomplished players was! showing consistently about 7 to 10 percent higher ball velocities than conventional racquets because of, . . . (2) the longitudinal moment of inertia of the oversize racquetball racquet! is approximately 30 percent higher than a conventional racquetball racquet! ... that the main and the cross strings . . . in the impact zone are 30 to 40 percent longer . . . . "
2.2 Limitations on Racquet Size
In summary, the prior art can fairly be said to suggest, if not forthrightly teach, that larger racquets which have, innately, longer strings have discernably different, and arguably better, properties of play. Based on this history, and this rationale, it would be expected that gigantic racquets would have appeared somewhere, sometime, in most if not all racquet sports. Alas, there are countervailing considerations to making racquets ever larger. Clearly the general limitations of space, weight and manipulation difficulties posed by racquets of extreme large size limit the physical size of these racquets. In addition, most racquet sports (as well as other sports including golf and hockey) have rules that, among other things, regulate the physical characteristics of the equipments with which the sport is played.
Ruling bodies, such as the International Tennis Federation (ITF), and American Amateur Racquetball Association (AARA), have placed geometric limits on racquets used in events under their respective sanctions. This tends to guide racquet manufacturers into compliance with the limitations. For example, tennis rackets shall not exceed 32 inches in overall length.
Further by example, and by way of illustration, the racquet sport of racquetball is predominantly (if not exclusively) regulated by the rules of the American Amateur Racquetball Association (AARA). The AARA rules require that the overall length of a racquetball racquet should not exceed twenty one inches (21").
The nature of the game of racquetball, and the use of racquetball racquets therein, has so far required that the racquetball racquet should have a peripheral handle. The absolute minimum size handle that a very few adult players with extremely small hands can use effectively is three and one half-inch inches (31/2") in length. The practical minimum handle length for a commercially sold racquet is four inches (4"), but a large percentage of racquet sports players will complain about a handle of this length as being "too short", and will be highly resistant to purchase a racquetball racquet having such a short handle. Most players normally require a handle for gripping a racquetball racquet which handle is greater than four inches (4") in length, and which is more commonly more than five inches (5") in length.
Moreover, each string of a racquet must be connected at each of its ends to the racquet frame. If two times one-half inch (2.times.1/2"), or one inch (1") total, is considered to be the combined thickness of the frame at the two opposing connection points to which a string is routed, and five inches (5") is considered to be the nominal length of the handle, then the subtraction of these necessary minimum distances from the twenty-one inch (21") maximum length of the frame makes that the maximum length of the longitudinal strings is limited to approximately fifteen inches (15").
This has in fact been the case. Because of the necessary thickness of the frame and length of the handle, the maximum length of the main strings of racquetball racquets--routed along the major axis of the racquet, which axis runs through the handle--has heretofore been less than fifteen inches (15"). The longest racquetball racquet strings previous to the present invention known to the inventors were the 14.8" to 14.9" strings appearing on the EMINENCE.TM. and ALUSION.TM. model racquetball racquets manufactured by Ektelon corporation; the 14.9" strings appearing on the GRAPHITE ASSAULT.TM. model racquetball racquet manufactured by Spalding corporation; the 14.9" strings appearing on the PHASE II.TM. model racquetball racquet manufactured by Transition Sports corporation; and 14.8" to 14.9" strings appearing on the REAL DEAL model racquetball racquet manufactured by EF Composite Technologies, Limited Partnership (assignee of the present invention).
2.3 Dynamics of Stringed Racquets
Large racquets generally play better than small racquets within the considerable limits of considerations related to (i) air resistance, (ii) moment of inertia, (iii) center of gravity, (iv) moment of the lever arm presented by the handle and grip, (v) string and frame materials, and (vi) the contact with, and the energy imparted to, various types and speeds of balls upon various strokes of a racquet as may be administered by various players.
It is not difficult to discover that the dynamics of the sport of racquetball, in particular, and the striking of a regulation racquetball ball, could greatly benefit from a larger racquet. It is much easier and more effective to accelerate a racquetball ball to high velocity by "serving" with a tennis racquet as opposed to a racquetball racquet, as may be conveniently determined by sports radar in an outdoor environment. It is also possible to build oversize, non-conforming racquetball racquets and to exercise, and to quantify the performance of, these racquets in play, including in competitive play between experts on regulation racquetball courts.
However, and as previously discussed, there are competing considerations to increasing the size of racquets. It would accordingly be desirable if some of the dynamical performance advantages of an oversize racquet could somehow be incorporated into existing smaller, and/or regulation, racquets. The present invention concerns all racquets--including but not limited to tennis racquets and squash racquets and badminton racquets and racquetball racquets (both regulation AARA-qualified and not so qualified). The present invention is directed to improving racquets of all types so as to realize the dynamics, and the "play-ability" of much larger racquets in a smaller form factor.